Discovery of Resilience of Large and Complex Aquifers to Climatic Extremes under Anthropogenic Influences

In the face of intensified climatic extremes and global aquifer stress, a subtle understanding of the complex dynamics of large aquifer systems is necessary. This study delves into the impact of changing climate and anthropogenic activities on hydro-geologically diverse regions crucial for sustaining agricultural activities. Our central hypothesis is that excessive anthropogenic activities may disrupt the connection between groundwater levels and their primary recharge source—precipitation. Leveraging advanced non-linear signal processing technique of cross-wavelet transform, we explore non-linear relationships between groundwater and precipitation. Our findings underscore the complexity of interactions between surface and sub-surface processes in the sub-tropical basins.  A crucial threshold emerges at the basin scale, as the disconnection occurs when the water table falls below 4-5 meters. Intriguingly, at the basin and subbasin scale, the connection between groundwater and precipitation has significantly weakened and broken post the drought year 2002, emphasizing the localized and enduring impact of pumping activities. The recovery from these extremes, vital for sustaining agriculture, is intricately linked to the intensity of anthropogenic activities. This research contributes valuable insights into how the groundwater response to precipitation is changing with time in highly developed large subtropical aquifers facing increasing frequency of droughts. The results will aid in formulating region-specific groundwater management strategies to enhance the resilience of groundwater resources to global warming and climate change.